PREDICTIVE FACTORS FOR SPONTANEOUS CLOSURE OF ATRIAL SEPTAL-DEFECTS DIAGNOSED IN THE 1ST 3 MONTHS OF LIFE

Objectives. To establish the rate of spontaneous closure of atrial sep tal defects diagnosed before age 3 months, 101 infants (mean age 26 da ys) with an interatrial shunt confirmed by Doppler echocardiography we re followed up for an average of 265 +/- 190 days. Background. Even if interatrial shunts in the newborn are frequently encountered, little is known about their natural history. Methods. Defect diameter on two- dimensional echocardiography and width of color flow jet were measured in the subcostal view. Right and left ventricular diameters and atria l septal curvature were also studied. Kaplan-Meier curves were obtaine d to predict age of spontaneous closure in relation to initial defect diameter. Results. There was no significant correlation between the di ameter of the atrial septal defect and right ventricular/left ventricu lar ratio or type of septal curvature (vertical or concave toward the left atrium). The classic predominance of girls over boys was observed only for defects >5 mm. An overall rate of spontaneous closure of 87% was observed. Frequency and timing of closure were inversely correlat ed to atrial septal defect diameter: closure occurred in 100% (32 of 3 2) of defects in group 1 (diameter <3 mm), 87% of defects (39 of 45) i n group 2 (diameter 3 to 5 mm), 80% of defects (16 of 20) in group 3 ( diameter 5 to 8 mm). Spontaneous closure did not occur in four patient s of group 4 (defect greater-than-or-equal-to 8 mm) during an average follow-up interval of 417 days (range 294 to 597 days). Conclusions. T hese results suggest that infants with an atrial septal defect <3 mm n eed not be followed up as 100% of these defects will be closed by age 18 months; those with a defect 3 to 5 or 5 to 8 mm should be evaluated by the end of the 12th and the 15th month, respectively, when >80% of these defects will be closed. An atrial septal defect with a diameter greater-than-or-equal-to 8 mm may have little chance of closing spont aneously and the possibility of surgical correction should be consider ed. Defects <3 mm probably do not constitute a cardiac malformation in light of their natural evolution and gender distribution.